On Mon, Dec 17, 2018 at 09:31:06AM -0800, Sean Christopherson wrote: > This doesn't work as-is. sgx_encl_release() needs to use sgx_free_page() > and not __sgx_free_page() so that we get a WARN() if the page can't be > freed. sgx_invalidate() needs to use __sgx_free_page() as freeing a page > can fail due to running concurrently with reclaim. I'll play around with > the code a bit, there's probably a fairly clean way to share code between > the two flows. Hmm... but why issue a warning in that case? It should be legit behaviour. > sgx_encl_release_worker() calls do_unmap() without checking the validity > of the page tables[1]. As is, the code doesn't even guarantee mm_struct > itself is valid. > > The easiest fix I can think of is to add a SGX_ENCL_MM_RELEASED flag > that is set along with SGX_ENCL_DEAD in sgx_mmu_notifier_release(), and > only call do_unmap() if SGX_ENCL_MM_RELEASED is false. Note that this > means we cant unregister the mmu_notifier until after do_unmap(), but > that's true no matter what since we're relying on the mmu_notifier to > hold a reference to mm_struct. Patch attached. OK, the fix change makes sense but I'm thinking that would it be a better idea just to set mm NULL and check that instead? /Jarkko
